DENVER — The owners of a bankrupt Colorado cantaloupe farm whose listeria-tainted melons killed 33 people in 2011, in one of the deadliest outbreaks of food-borne illness on record in the United States, have been arrested and charged, federal prosecutors said Thursday.

Eric Jensen, 37, and his brother Ryan, 33, former owners of Jensen Farms in Granada, Colo., were each charged with six counts of “introducing adulterated food into interstate commerce,” U.S. Attorney John Walsh said in a statement.

In May 2011, the Jensens began washing their farm’s cantaloupe crop with equipment designed to clean potatoes and failed to use a chlorine spray feature that kills deadly bacteria, prosecutors said.

“The defendants were aware that their cantaloupes could be contaminated with harmful bacteria if not sufficiently washed,” the federal prosecutors said in the statement. “The chlorine spray, if used, would have reduced the risk of microbial contamination of the fruit.”

Aside from the fatalities linked to cantaloupes from Jensen Farms, 147 people across 28 states were hospitalized, and a woman suffered a miscarriage, authorities said.

The elderly, pregnant women and people with weakened immune systems are most at risk of falling ill from listeria, according to the Centers for Disease Control and Prevention.

Symptoms include fever and muscle aches, sometimes preceded by diarrhea and other gastrointestinal problems.

Listeria infections are typically linked to certain cheeses and packaged meats, and this was the first outbreak in the United States tied to cantaloupes.

Months after the Jensen produce went to market, health officials in over two dozen states reported a spike in listeria infections from people who ate cantaloupes from Colorado.

The outbreak was ultimately traced to fruit shipped from Jensen Farms.

Investigators with the Food and Drug Administration inspected the Jensen Farms packing plant at the time and said they found “poor sanitary practices in the facility.”

The Jensens filed for bankruptcy and shuttered their operation after they were hit with a spate of lawsuits.

Bill Marler, a Seattle-based lawyer who represents some families of people killed or sickened by the outbreak, said he was “pleased that some form of criminal sanctions” was leveled against the Jensens. But he said retailers such as Wal-Mart and Kroger that sold the tainted melons, and which he is also suing, should likewise be held criminally accountable.

The brothers surrendered to U.S. marshals on Thursday and made an appearance before a magistrate judge in Denver later in the day, where their attorneys entered not guilty pleas on their behalf.

U.S. District Magistrate Judge Michael Hegarty set trial for Dec. 2.

Both brothers were released on $100,000 secured bonds.

Attorneys for both men said in a joint statement that the brothers have “fully cooperated” with the authorities.

“As they were from the first day of this tragedy, the Jensens remain shocked, saddened and in prayerful remembrance of the victims and their families,” the attorneys’ statement said.

If convicted, the brothers each face a maximum one-year prison sentence, and up to $250,000 in fines for each of the charges.